In the past, an optical measurement method using flow cytometry (a flow cytometer) has been used to analyze living body-related microparticles such as a cell, a microorganism, and a liposome. The flow cytometer is a device that radiates light to microparticles flowing through a flow channel formed in a flow cell or a microchip, detects fluorescent light or scattered light emitted from the individual microparticles, and analyzes the microparticles.
The flow cytometer includes a function of sorting only the microparticles having a specific characteristic, on the basis of an analysis result, and collecting the microparticles. Particularly, a microparticle device sorting cells is referred to as a “cell sorter”. Generally, in the cell sorter, vibration is applied to a flow cell or a microchip by a vibration element to make a fluid discharged from a flow channel become liquid droplets (refer to PTL 1 and 2).
After positive (+) or negative (−) charges are applied to the liquid droplets separated from the fluid, an advancement direction of the liquid droplets is changed by a deflection plate and the liquid droplets are collected to a predetermined container. In addition, technology for distributing one specific cell to each reaction portion of a base material used for a polymerase chain reaction (PCR) method, using the sorting function by the cell sorter, is also suggested in the past (refer to PTL 3).